Vertical hall sensor with high electrical symmetry

ABSTRACT

A vertical Hall sensor includes a Hall effect region and a plurality of contacts formed in or on a surface of the Hall effect region. The plurality of contacts are arranged in a sequence along a path extending between a first end and a second end of the Hall effect region. The plurality of contacts includes at least four spinning current contacts and at least two supply-only contacts. The spinning current contacts are configured to alternatingly function as supply contacts and sense contacts according to a spinning current scheme. The at least four spinning current contacts are arranged along a central portion of the path. The at least two supply-only contacts are arranged on both sides of the central portion in a distributed manner and are configured to supply electrical energy to the Hall effect region according to an extension of the spinning current scheme.

RELATED APPLICATION

This application is related to U.S. Ser. No. 13/187,935 filed on Jul.21, 2011 entitled “ELECTRONIC DEVICE WITH RING-CONNECTED HALL EFFECTREGIONS”.

FIELD OF THE INVENTION

Embodiments of the present invention relate to a vertical Hall sensorand to a magnetic sensing method using a vertical Hall sensor.

BACKGROUND OF THE INVENTION

In order to sense or measure the strength and direction of a magneticfield parallel to the surface of, e.g., a semiconductor die, verticalHall devices may be used. Most vertical Hall devices suffer from thefact that the spinning current method, which is used to cancel thezero-point error of the Hall devices, does not work very well. Withknown methods of the spinning current scheme, it is possible to obtainresidual zero-point errors of about 1 mT. A reason for this rather pooroffset behavior can be found in the asymmetry of the vertical Halldevice. Although it is known how to connect four vertical Hall devicesin order to improve the symmetry, the contact resistances may stillcause residual asymmetries.

SUMMARY

Embodiments of the present invention provide a vertical Hall sensor thatcomprises a Hall effect region and a plurality of contacts formed in oron a surface of the Hall effect region. The contacts are arranged in asequence along a path extending between a first and a second end of theHall effect region. The plurality of contacts comprise at least fourspinning current contacts and at least two supply-only contacts. Thespinning current contacts are configured to alternatingly function as asupply contact and a sensor contact according to a spinning currentscheme. The at least four spinning current contacts are arranged along acentral portion of the path. The at least two supply-only contacts arearranged on both sides of the central portion in a distributed mannerand are configured to supply electrical energy to the Hall effect regionaccording to an extension of the spinning current scheme for supplyingelectrical energy to the Hall effect region.

Further embodiments of the present invention provide a vertical Hallsensor comprising a Hall effect region and a plurality of contactsformed in or on a Hall effect region in a sequence along a pathextending between a first end and a second end of the Hall effectregion. The contacts are consecutively numbered according to thesequence. The plurality of contacts comprises first type contacts andsecond type contacts, wherein M second type contacts are arrangedbetween every two first type contacts, M being a positive integer. Firsttype contacts having ordinal numbers within the sequence given by1+i*4*(1+M), i=0, 1, 2 . . . are connected to a first node N1. Firsttype contacts having ordinal numbers within the sequence given by2+M+i*4*(1+M), i=0, 1, 2 . . . are connected to a second node N2. Firsttype contacts having ordinal numbers within the sequence given by3+2*M+i*4*(1+M), i=0, 1, 2 . . . are connected to a third node N3.Finally, first type contacts having ordinal numbers within the sequencegiven by 4+3*M+i*4*(1+M), i=0, 1, 2 . . . are connected to a fourth nodeN4. The first type contacts are considered to alternatingly function assupply contacts and as sense contacts according to a spinning currentscheme with provision to supply electrical energy between the first andthird nodes N1, N3 in a first operating phase of the spinning currentscheme and between the second and fourth nodes N2, N4 in a secondoperating phase. The first type contacts are also configured to sense asense signal between the second and fourth nodes N2, N4 in the firstoperating phase and to sense another sense signal between the first andthird nodes N1, N3 in the second operating phase. The second typecontacts are floating contacts.

Further embodiments of the present invention provide a vertical Hallsensor comprising a Hall effect region and a plurality of contactsformed in or on a surface of the Hall effect region. The Hall effectregion has a first end and a second end. The Hall effect region issymmetric with respect to a symmetry axis such that the first and thesecond ends are mirror-inverted to each other with respect to thesymmetry axis. The plurality of contacts are formed in a symmetricalmanner with respect to the symmetry axis. The contacts are arranged in asequence along a path extending between the first end and the second endof the Hall effect region. The plurality of contacts comprises at leastfour spinning current contacts and at least two supply-only contacts.The spinning current contacts are configured to alternatingly functionas supply contacts and as sensor contacts according to the spinningcurrent scheme. The at least four spinning current contacts are closerto the symmetry axis than the supply-only contacts. The at least twosupply-only contacts are configured to supply electrical energy to theHall effect region such that boundary effects affecting an electriccurrent flow within the Hall effect region during an execution of aspinning current scheme are reduced, the boundary effects being causedby at least one of the first and second ends.

Furthermore, embodiments of the present invention provide a magneticsensing method which comprises connecting a power supply between aspinning current contact and a supply-only contact, sensing a sensesignal, swapping the functions of the spinning current contacts, sensinganother sense signal, and determining an output signal. The spinningcurrent contact is configured to alternatingly function as a supplycontact and as a sense contact according to the spinning current scheme.The spinning current contact and the sense contact belong to a pluralityof contacts formed in or on a surface of a Hall effect region of avertical Hall sensor. The plurality of contacts comprises at least fourspinning current contacts and at least two supply-only contacts. Thecontacts are arranged in a sequence along a path extending between afirst end and a second end of the Hall effect region, wherein the atleast four spinning current contacts are arranged along a centralportion of the path. The at least two supply-only contacts are arrangedon both sides of the central portion in a distributed manner and areconfigured to supply electrical energy to the Hall effect regionaccording to an extension of the spinning current scheme for supplyingelectrical energy to the Hall effect region. The action of sensing asense signal is performed between at least two spinning current contactscurrently functioning as sense contacts. The action of swapping thefunctions of the spinning current contacts has the effect that theelectrical energy is now supplied to the Hall effect region via thespinning current contacts having previously functioned as sense contactsand at least one other supply-only contact different from thesupply-only contact used before. The other sense signal is sensedbetween two spinning current contacts other than the ones usedpreviously. The output signal is determined on the basis of the sensesignals.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention are described herein, makingreference to the appended drawings.

FIG. 1 a shows a schematic plan view and a corresponding schematic crosssection of a vertical Hall sensor during a first operating phase (top)and a second operating phase (bottom) of a spinning current scheme;

FIG. 1 b shows a schematic plan view of a vertical Hall sensor using onesupply contact more in the first and second operating phase than thevertical Hall sensor shown in FIG. 1 a;

FIG. 1 c shows schematic plan views of a vertical Hall effect sensoraccording to an embodiment of the teachings disclosed herein in a firstand a second operating phase, respectively;

FIG. 1 d shows schematic plan views of a vertical Hall sensor during afirst and a second operating phase, respectively, to illustrate howdifferential sensor signals may be tapped at the sensor contacts in anested manner;

FIG. 2 illustrates an extension of tapping differential sensor signalsat the sense contact in a nested manner;

FIG. 3 shows schematic plan views of a vertical Hall device having twoHall effect regions in a first and a second operating phase,respectively;

FIG. 4 shows schematic plan views of another vertical Hall sensor havingtwo Hall effect regions in a first and a second operating phase,respectively;

FIG. 5 shows schematic plan views of a vertical Hall sensor having twoHall effect regions according to an embodiment of the disclosedteachings in a first and a second operating phase, respectively;

FIG. 6 shows schematic plan views of vertical Hall sensors in a firstand a second operating phase, respectively;

FIG. 7 shows schematic plan views of a vertical Hall sensor according toan embodiment of the disclosed teachings during a first and a secondoperating phase, respectively;

FIG. 8 shows a schematic plan view of a vertical Hall sensor with anL-shaped Hall effect region according to an embodiment of the disclosedteachings;

FIG. 9 shows a schematic plan view of a vertical Hall sensor having anarch-shaped Hall effect region according to an embodiment of thedisclosed teachings;

FIG. 10 shows schematic plan views of a Hall effect sensor according toan embodiment of the disclosed teachings during a first and a secondoperating phase, respectively;

FIG. 11 shows a schematic plan view of a vertical Hall sensor accordingto an embodiment of the disclosed teachings similar to the one shown inFIG. 11;

FIG. 12 a shows a schematic plan view of a vertical Hall sensor having asquare, ring-like Hall effect region;

FIG. 12 b shows a schematic cross-section of the vertical Hall deviceshown in FIG. 12 a;

FIG. 12 c shows another schematic cross-section of the vertical Halldevice shown in FIG. 12 a;

FIGS. 13 a, 13 b show a vertical Hall sensor having a square, ring-likeHall effect region in a first operating state and a second operatingstate of the spinning current scheme;

FIGS. 14 a, 14 b show another vertical Hall sensor having a ring-like,square Hall effect region during a first operating phase and a secondoperating phase, respectively; and

FIG. 15 shows a schematic flow diagram of a magnetic sensing methodaccording to an embodiment of the disclosed teachings.

Equal or equivalent elements or elements with equal or equivalentfunctionality are denoted in the following description by equal orsimilar reference signs.

DETAILED DESCRIPTION

In the following description, a plurality of details are set forth toprovide a more thorough explanation of embodiments of the teachingsdisclosed herein. However, it will be apparent to one skilled in the artthat embodiments of the teachings disclosed herein may be practicedwithout these specific details. Features of the different embodimentsdescribed hereinafter may be combined with each other, unlessspecifically noted otherwise. For the most part, the terms “Hall effectregion” and “tub” are used interchangeably herein. Accordingly, a Halleffect region may be a tub or a well of a first conductivity type whichis embedded in a substrate or a tub of an opposite conductivity type.This structure may cause an electrical isolation of the tub against thesubstrate in particular if the resulting PN-junction is reversed biased.

When the vertical Hall sensor comprises two or more Hall effect regions,these may be isolated from each other. The electrical isolation of twoHall effect regions against each other may take several forms. Accordingto a first form of isolation, the two or more Hall effect regions aredisjoined from each other, i.e., two adjacent Hall effect regions do notmerge at one or more locations but are separated by a material otherthan the Hall effect region material. As one possible option, the tubmay be isolated in a lateral direction by means of trenches that aretypically lined and/or filled with a (thin) oxide. As another option,the tub may be isolated towards the bottom by means of an SOI (siliconon insulator) structure. Although the tub typically has a singleconductivity type, it may be advantageous to configure the dopingconcentration in an inhomogeneous manner, i.e., spatially variable. Inthis manner, a high concentration of the doping agent may occur in thearea of the contact, as is usual with deep tub contacts, for example inCMOS technology. In the alternative, a layering of differently stronglydoped layers may be sought after as is the case with, e.g., a buriedlayer. Such a layering may result, to some extent, from technologicalreasons relative to other electronic structures that are formed withinthe substrate. The design of the vertical Hall sensor may need to bereconciled with these circumstances, even though the layering may, infact, be unfavorable for the vertical Hall sensor.

Another form of isolation may be achieved by measures that reduce orsubstantially prevent an electric current from flowing in one or moresubregions of a tub or well. For example, the electric current may beoffered an alternative current path that has lower ohmic resistance(possibly by several orders of magnitude) than a substantially parallelcurrent path would have that goes through the tub. The current pathhaving the lower ohmic resistance may be a conductor formed in or on thesurface of the tub.

Preferably, the Hall effect region may be an n-doped semiconductor asthis provides an approximately three times higher mobility andconsequently a higher Hall factor than with a p-doped semiconductor. Thedoping concentration in the functional part of the Hall effect region istypically in the range of 10¹⁵ cm⁻³ to 10¹⁷ cm³.

Another possible material for the Hall effect regions is permalloy whichis a nickel-iron magnetic alloy, or a material similar to permalloy.Permalloy exhibits a low coercivity, near zero magnetostriction, highmagnetic permeability, and significant anisotropic magnetoresistance. Avariation of the electrical resistance of permalloy within a range ofapproximately 5% can typically be observed depending on the strength andthe direction of an applied magnetic field. This effect may be used in asimilar manner as the Hall effect occurring in a semiconductor forsensing and/or measuring a magnetic field, and it is known in theliterature as anomalous Hall effect.

The teachings disclosed herein are related to the use of the spinningcurrent principle, in which supply terminals and sense terminals areexchanged in consecutive clock phases/operating phases. A sense terminalin a vertical Hall sensor responds to an electric current passingunderneath it. A magnetic field (parallel to a die surface andperpendicular to the current streamline) can efficiently lift up or pulldown the potential at the contact (which typically is at the surface ofthe die). Contacts at the end of a tub (or a Hall effect region)typically are not, or only negligibly, subject to current streamlinespassing underneath them. Therefore, contacts at the ends of a tubtypically are less frequently used as sense contacts.

When using the spinning current principle for vertical Hall devices, onechallenge is the fact that typical vertical Hall devices are notsymmetric, in terms of an interchangeability of supply contacts andsense contacts. However, the spinning current principle typically needsa highly symmetric device. A typical vertical Hall device may have ashape of a brick with several contacts. Some of the contacts are closerto one of the ends of the brick than other (more central) contacts. Forthis reason the outer contacts, when used as supply contacts, generatedifferent potential distributions in the brick than the inner contacts.Therefore, if the spinning current principle periodically exchangesinput with output terminals, the symmetry of the potential distributionswill be poor.

According to one aspect of the teachings disclosed herein, the brick maybe stretched and only the inner contacts may be used so that the outercontacts are far away and are not used for the output signal while theinner contacts are almost perfectly symmetric.

Besides sensing Hall effect-related sense signals primarily in a centralportion of the Hall effect region, i.e., typically relatively far awayfrom a first end and a second end of a Hall effect region with respectto a longitudinal direction, the following measures may also favor amore symmetric behavior of the vertical Hall sensor: using supply-onlycontacts and/or providing floating contacts between each two (adjacent)spinning current contacts. Typically, there is an even number of thesupply-only contacts with one half of the supply-only contacts beingarranged at one side of a central region in which the spinning currentcontacts are located, and the other half being arranged on the otherside of the central region, in order to maintain the symmetry of thevertical Hall sensor. Vertical Hall sensors having four supply-onlycontacts appear to perform quite well with respect to improving thesymmetry of the vertical Hall sensor and thus reducing the residualzero-point error. Nevertheless, embodiments having only two supply-onlycontacts may be conceived as well. Likewise, vertical Hall sensorshaving six or more supply-only contacts may also be designed. In thevicinity of each supply-only contact, the current density distributionmay be subject to influences caused by either the first end or thesecond end of the Hall effect region, whichever is closer to thesupply-only contact at hand. When approaching the central region andwithin the central region, however, the current density distributionbecomes more and more homogeneous. In other words, local irregularitiescaused by the first end or the second end of the Hall effect region haveonly a relatively small influence on the current density distribution inthe central region of the Hall effect region. Another possible reasonfor an inhomogeneous current density distribution within the Hall effectregion may be found in the need for the electric current to change itsdirection of current flow twice while flowing through the Hall effectregion. This phenomenon is believed to not only affect those supplycontacts or supply-only contacts that are relatively close to the firstend or the second end of the Hall effect region, but basically allsupply contacts and supply-only contacts. The supply-only contacts, thatare relatively far away from the central region of the Hall effectregion, may level out, on average, the irregularities in the currentdensity distribution within the central region up to a certain degree.In particular, the current density distribution in the central regionduring the first operating phase is typically much more similar to thecurrent density distribution within the central portion during thesecond operating phase, except for the fact that the direction ofcurrent flow may be opposite in the second operating phase compared tothe first operating phase, at least in some sections of the Hall effectregion. This inversion of the current flow is, however, intentional andmay be taken into account when determining the output signal of thevertical Hall sensor. In summary, the symmetry of the device can beincreased by means of the supply-only contacts at the expense of aslightly increased current consumption.

According to the teachings disclosed herein, it is also possible toprovide one or more floating contacts between each two adjacent spinningcurrent contacts. These floating contacts are also called second typecontacts in other parts of this disclosure. Floating contacts arelow-ohmic compact regions at the surface (i.e., an accessible side) ofthe Hall effect region that are neither used for the purpose ofsupplying electrical energy nor for tapping a sense signal. Floatingcontacts may be used to influence the electric potential in the wellsimilar to the gate of a CMOS transistor. As an alternative, thefloating contacts could be highly doped wells that are not necessarilycontacted to a metal region. Yet another alternative is that thefloating contacts could be wells having a high doping concentration thatare contacted to one or more metal spots by means of a contact plug. Thefloating contacts have the following effect: the current flow is pulledcloser to a middle line of the Hall effect region extending between thefirst end and the second end in a substantially parallel or coincidingmanner with the path along which the spinning current contacts (firsttype contacts) and the floating contacts (second type contacts) arearranged. Floating contacts that are smaller than the spinning currentcontacts and/or the supply-only contacts are particularly efficient inconcentrating the current flow around the middle line of the Hall effectregion. Note that the desired homogeneity of the current flow is mainlyimportant in the longitudinal direction, i.e. parallel to the path alongwhich the contacts are arranged. Pulling the current flow towards themiddle line may be important when, due to process technological reasonsit is not possible that the first type contacts extend over the entirewidth of the Hall effect region: in this case, the magnetic sensitivityis reduced due to portions of the electric current that flow in adirection parallel to the component of the magnetic field to be sensed(i.e., the y-direction according to the coordinate system used in mostof the figures). In order to prevent/avoid these portions of thecurrent, the floating contacts are arranged near the middle line whichpull the current to the middle.

FIG. 1 a shows, in the upper half, a schematic plan view of a verticalHall sensor and a corresponding cross-section of the same vertical Hallsensor during a first operating phase or clock phase of a spinningcurrent scheme or cycle. In the lower half, FIG. 1 a shows the schematicplan view and a schematic cross-section of the same vertical Hall sensorduring a second operating phase of the spinning current scheme. Thevertical Hall sensor comprises a Hall effect region 11 that may beformed in a semiconductor substrate by locally doping the semiconductorsubstrate to obtain, e.g., an n-type semiconductor material (an n-typesemiconductor has more electrons than holes). By locally doping thesemiconductor substrate a well or a tub is formed within thesemiconductor substrate. The well or tub may then be used as the Halleffect region 11. A plurality of contacts is formed in, or on a surfaceof, the Hall effect region 11. The plurality of contacts in oneembodiment comprises four spinning current contacts 21, 22, 23, and 24.During the first operating phase of the vertical Hall sensor, thespinning current contacts 21 and 22 function as supply contacts. To thisend, the spinning current contacts 21 and 22 are connected to a voltagesupply 81. As an alternative to the voltage supply 81, a current sourcecould be used as well. The two other spinning current contacts 23 and 24are configured to function, during the first operating phase, as sensecontacts so that they are connected to a voltage sensing element 91.During operation, the voltage supply 81 causes an electric current toflow to the spinning current contact 21 (supply voltage in operatingphase 1), through a portion of the Hall effect region 11, therebypassing the spinning current contact 24 (sense contact), to the spinningcurrent contact 22 (supply contact), and back to the voltage supply 81.A magnetic field By in the y-direction, i.e., parallel to the surface ofthe Hall effect region 11 and perpendicular to a longitudinal extensionof the Hall effect region 11, has an influence on the electric chargecarriers constituting the electric current within the portion of theHall effect region extending between the supply contacts 22 and 21. Aresult of this influence is a variation of an electric potential at thesense contact 24, wherein the variation is a function of the magneticfield By in the y-direction. The variation of the electric potential atthe sense contact 24 is referred to the sense contact 23 and acorresponding differential electric voltage can be sensed by the sensingelement 91.

The contacts that are formed in or on the surface of the Hall effectregion 11 may be referred to either by their reference numeral or bytheir ordinal number. Whenever possible, the reference numbers have beenassigned (by definition) to the various contacts on the basis of afunction of the particular contact during the first operating phase. Forexample, the spinning current contacts 21 to 24 have reference numeralsin the 20s, whereas supply-only contacts have reference numbers in the30s. In contrast, the ordinal numbers reflect a spatial arrangement ofthe contacts. The contacts may be thought of as arranged in a sequencealong a path extending between a first end and a second end of the Halleffect region 11. In the figures the ordinal numbers are the numberswhich are illustrated directly adjacent or within the correspondingcontact. The ordinal numbers have an ascending order typically from leftto right. To give an example: the spinning current contact 21 has theordinal number 6. As a shorthand notation for the ordinal numbers thehash key symbol # will be used, e.g., “contact #6” for the justmentioned spinning current contact 21 which is at the sixth positionfrom the left.

In the figures, an effort has been made to indicate a function of eachcontact during the operating phases of the spinning current scheme.Spinning current contacts currently functioning as supply contacts aresolid white or solid black, depending on the pole of the voltage supply81 they are connected to (positive pole: black; negative pole: white).Spinning current contacts currently functioning as sense contacts have arelatively dark, upward hatching (e.g., spinning current contact 23) ora relatively light, downward hatching (e.g., spinning current contact24), depending on the pole of the sensing element 91 to which aparticular sense contact is connected. Supply-only contacts, which willbe explained in more detail below, are also solid white or solid black,depending on how they are connected to the voltage supply 81. Contactsthat are floating during the first operating phase may have one of thefollowing four patterns: small checkerboard pattern (e.g., contact withordinal number 2), cross-hatching (e.g., contact with ordinal number 8),dense vertical hatching (e.g., contact with ordinal number 3), andhorizontal hatching (e.g., contacts with ordinal numbers 1 and 9); theseassignments being valid for FIG. 1 a and not necessarily for otherfigures).

The vertical Hall sensor shown in FIG. 1 a comprises a plurality offloating contacts 64-1, 61, 63, 62, and 64-2. The floating contacts64-1, 61, and 63 are arranged on one side of the four spinning currentcontacts 21 to 24. The other two floating contacts 62 and 64-2 arearranged on another side of the four spinning current contacts 21 to 24.Due to the floating contacts 61, 62, 63, 64-1, and 64-2, the regularcontact structure that is formed in or on the surface of the Hall effectregion 11 does not abruptly end at the two outer spinning currentcontacts 22 and 23, but is continued (or extrapolated) for a fewcontacts. Thus, a distance between the two outer spinning currentcontacts 22, 23 to the first end or the second end of the Hall effectregion 11 can be increased without introducing another source forinhomogeneity at the edges of a central portion of the Hall effectregion 11 in which the four spinning current contacts 21 to 24 arearranged.

The lower half of FIG. 1 a shows the vertical Hall sensor during asecond operating phase of the spinning current scheme. The functions ofthe spinning current contacts 21 to 24 have been swapped so that thevoltage supply 81 is now connected to spinning current contacts 23, 24,while the sensing element 91 is connected to the spinning currentcontacts 21, 22. Following the principle that a fill pattern of acontact typically illustrates its current function, the spinning currentcontact 23 is illustrated as solid black, the spinning current contact24 is illustrated as solid white, the spinning current contact 21 isillustrated with a dark, upward hatching, and the spinning currentcontact 22 is illustrated with a bright, dark numbered hatching.Although they are not connected to any other circuitry in FIG. 1 a, thefill patterns of the floating contacts 61, 62, 63, 64-1 and 64-2 arealso changed in the lower half of FIG. 1 a with respect to the upperhalf thereof.

The operation of the vertical Hall sensor shown in FIG. 1 a may bedescribed as follows: in a first clock phase (operating phase) a voltagesource 81 is connected to two inputs having the ordinal numbers 4 and 6.A sense element or voltmeter 91 is connected to the two outputs with theordinal numbers 5 and 7. In the second operating phase, the inputs andthe outputs are exchanged: the voltage source 81 is connected to the twoinputs with the ordinal numbers 5 and 7 and the voltmeter 91 (or anothervoltmeter) is connected to the two outputs with ordinal numbers 4 and 6.In an optional third operating phase, the voltage source 81 and thevoltmeter 91 are connected to the same contacts as in the firstoperating phase, but with reversed polarity. In an optional fourthoperating phase the voltage source 81 and the voltmeter 91 (or the othervoltmeter) are connected to the same contacts as in the second operatingphase, but with reversed polarity. All other contacts (i.e., contactswith the ordinal numbers 1, 2, 8, and 9) are left floating. Instead ofmeasuring the differential output voltage between the contacts withordinal numbers 5 and 7 in the first operating phase, one may measureonly the electric potential at the contact having ordinal number 5(referred to ground potential). Analogously, instead of measuring thedifferential output voltage between the contacts with ordinal numbers 4and 6 in the second operating phase, one may measure only the electricpotential at the contact with ordinal number 6.

Note that the Hall effect region 11 extends beyond the outmost contacts64-1 and 64-2. This is done in order to reduce the asymmetry of theouter contacts 64-1, 64-2, when compared with the inner contacts. Notealso that several outer contacts are not in use, meaning that they arenot supplied with electricity and there is no (volt) meter connected tothem: they are simply floating. They are used only for the purpose ofminimizing the asymmetry of the outer contacts. Effectively, only thefour spinning current contacts 21 to 24 are in use and the role ofinputs and outputs is exchanged in the two operating phases. Thecontacts are typically identical in size and are arranged on a regulargrid and positioned in a symmetric manner with respect to the Halleffect region 11 in order to maximize their symmetry. The two outmostcontacts 64-1 and 64-2 could be short-circuited (i.e., connected by aconductor) in one embodiment, in order to increase the symmetry(short-circuit not shown in FIG. 1 a).

FIG. 1 b shows two schematic plan views of a vertical Hall sensoraccording to an embodiment of the teachings disclosed herein in a firstoperating phase (top) and a second operating phase (bottom). Incomparison to the vertical Hall sensor shown in FIG. 1 a, the verticalHall sensor shown in FIG. 1 b is more symmetric. In the configuration ofa vertical Hall sensor shown in FIG. 1 b, some of the outer contacts areused to apply the electric energy to the device, in order to increasethe symmetry of the potential distribution. The improved vertical Hallstripe shown in FIG. 1 b comprises nine identical contacts in a Halleffect region 11 arranged on a regular grid along the x-axis in order tomeasure magnetic fields in the y-direction By. The vertical Hall sensoris the same as in FIG. 1 a, but the supply voltage is connected to onemore contact: in the first operating phase a contact 32 (ordinal number8) is additionally grounded and in the second operating phase a contact31 (ordinal number 3) is additionally tied to positive supply voltage asthis gives a better symmetry between contacts 24 and 23 (#5 and #7,respectively) in operating phase 1 and between contacts 22 and 21 (#4and #6, respectively). Therefore, at zero magnetic field By the outputvoltages in operating phase 1 and operating phase 2 are much closer tozero than in FIG. 1 a.

The contacts 31 and 32 are supply-only contacts, because they are onlyused as supply contacts throughout the spinning current scheme, but notas sense contacts (extension of the spinning current scheme orgeneralization thereof). The two supply-only contacts 31, 32 arearranged on both sides of a central portion of the plurality ofcontacts. The four spinning current contacts 22, 24, 21, and 23 arelocated in the central portion. The two supply-only contacts 31 and 32are arranged on both sides of the central portion in a distributedmanner, i.e., there are substantially as many supply-only contacts on afirst side of the central portion as on the second side thereof. Thelength of the Hall effect region 11 may be greater than a correspondinglength of the central portion by a factor comprised in a range between1.2 and 20, or a narrower range such as between 1.5 and 15, between 2and 10, or between 3 and 8. Supply-only contacts serve to supplyelectric energy in at least one of the operating phases of the spinningcurrent scheme, but they do not serve to sense a sense signal duringother operating phase(s). For example, they may be floating during theother operating phase(s).

The vertical Hall sensor comprises a second voltage supply 82 that isconnected to the spinning current contacts 21 and 22 during the firstoperating phase and to the spinning current contacts 23 and 24 duringthe second operating phase of the spinning current scheme.

Note that the contacts are symmetrical to the Hall effect region 11 inoperating phase 2, but not in operating phase 1: one might take accountof this by making the Hall effect region 11 slightly shorter at the leftside.

It is also possible to supply additionally the contact 61 (#2) withpositive supply voltage in operating phase 1 and the contacts 64-1, 64-2(#1 and #9, respectively) with the electric ground potential inoperating phase 2, in order to make the potential distribution even moresymmetric in both operating phases. This becomes apparent when lookingat the vertical Hall sensor from the perspective of the output contacts23 and 24 (#5 and #7, respectively) in operating phase 1 and from theperspective of the contacts 21 and 22 (#4 and #6, respectively) inoperating phase 2.

According to the embodiments shown in FIG. 1 b, the outmost contacts64-1 and 64-2 are not used as inputs for electrical energy. Instead, theoutmost contacts 64-1, 64-2 are floating contacts. Another floatingcontact is contact 61 (#2). In particular, a first floating contact 64-1of the at least two floating contacts 61, 64-1, 64-2 may be formed in oron the surface of the Hall effect region 11 between the first end andone supply-only contact 31 of the at least two supply-only contacts 31,32 that is closer to the first end than the other(s) of the at least twosupply-only contacts. A second floating contact 64-2 of the at least twofloating contacts is formed in or on the surface of the Hall effectregion 11 between the second end and one supply-only contact 32 of theat least two supply-only contacts that is closer to the second end thanthe other(s) of the at least two supply-only contact.

In cases where the outmost contacts and/or contacts that are not theoutmost contacts, but nevertheless relatively far out, are used assupply contacts, it may be possible to use a different input voltage orcurrent for these supply contacts in an effort to increase the symmetryof the potential distribution at zero magnetic field.

The sense contacts in both operating phases, i.e., contacts 23 and 24 inthe first operating phase and contacts 21 and 22 in the second operatingphase, are “framed” by supply contacts having different polarities. Forexample, the sense contact 24 during the first operating phase isadjacent to the supply contact 22 having negative polarity and, at theother side, adjacent to the supply contact 21 having positive polarity.Moreover, the directions of the electric currents passing by the sensecontacts 23, 24 during the first operating phase are opposite to eachother. The magnetic field in the y-direction acts on the electriccurrent flowing in opposite directions in the different portions of theHall effect region in an opposite manner: pushing the currentstreamlines towards the surface of the Hall effect region 11 near thesense contact 24 and pulling away the current streamlines from thesurface of the Hall effect region 11 near the sense contact 23, or viceversa. This leads to a relatively pronounced difference in the electricpotentials measured at the sense contacts 23, 24 and thus to arelatively high differential voltage that can be sensed or measured bythe sense element 91. The situation is similar during the secondoperating phase with respect to the contacts 21 and 22 functioning assense contacts during the second operating phase.

FIG. 1 c shows a plan view of a vertical Hall sensor according toanother embodiment of the disclosed teachings. In this embodiment, more“inner” contacts are used, so that the percentage of outer contacts isreduced. The vertical Hall sensor shown in FIG. 1 c comprises the Halleffect region 11, in or on the surface of which 21 identical contactsnumbered from 1 to 21 from left to right are arranged on a regular gridalong the x-axis in order to measure the magnetic field in they-direction By. The upper half of FIG. 1 c shows the vertical Hallsensor in its configuration for the first operating phase of thespinning current scheme and the bottom half of FIG. 1 c shows the samevertical Hall effect sensor in its configuration for the secondoperating phase.

During the first operating phase the contacts 31, 21-1, 21-2, 21-3, and21-4 function as positive supply contacts (indicated by the solid blackfilling) and are connected to a positive terminal of the voltage supply81. The contacts 22-1, 22-2, 22-3, 22-4, and 32 are configured tofunction as negative supply contacts during the first operating phase(indicated by the solid white filling) and are connected to a negativeterminal of the voltage supply 81. A first group of sense contactscomprises the contacts 23-1 to 23-4 (dark, upward hatching). Each of thesense contacts 23-1 to 23-4 is framed by a negative supply contact 22-ion the left and a positive supply contact 21-i on the right. The sensecontacts 23-1 to 23-4 are connected to two sense elements of a pluralityof sense elements V1 to V8. For example, the sense contact 23-1 isconnected to a second input of a sense element V1 and a first input of asense element V2. A second group of sense contacts comprises the contact24-1 to 24-5 (light, downward hatching), each of which is connected toone or two of the eight sense elements V1 to V8. Each one of the sensecontacts 24-1 to 24-5 is framed by a positive supply contact 31 or24-(i−1) on the left and a negative supply contact 22-i or 32 at theright.

The vertical Hall sensor also comprises two floating contacts 63-1 and63-5 as the outmost contacts, i.e., having the ordinal numbers 1 and 21,respectively.

The contacts having ordinal numbers from #3 to #19 are spinning currentcontacts which means that each one of the spinning current contactsfunctions as a supply contact during the first operating phase and asense contact during a second operating phase, or vice versa.Furthermore, the spinning current contacts are arranged along a centralportion of the Hall effect region. More precisely, the entire pluralityof contacts numbered 1 through 21 is arranged in a sequence along a pathextending between a first end (e.g., the left end) and a second end(e.g., the right end) of the Hall effect region 11. In theconfigurations shown in FIGS. 1 b and 1 c the path is not explicitlydepicted in the figures, but it can be derived from the arrangement ofthe contacts that the path is straight or rectilinear in both cases. Ingeneral, the path may have other forms as well, such as curved, angled,polygonal, or piece-wise straight. In the vertical Hall sensor shown asa schematic plan view in FIG. 1 c the central portion extends frombetween the contacts having ordinal numbers #2 and #3 to somewherebetween the contacts with the ordinal numbers #19 and #20.

During the second operating phase the spinning current contacts havechanged their respective functions so that former supply contacts 21-i,22-i now function as sense contact and former sense contacts 23-i, 24-ifunction as supply contacts.

The contacts 31 and 32 are supply-only contacts that function as supplycontacts during the first operating phase, but are left floating duringthe second operating phase. The spinning current scheme is applied orextended to the supply-only contacts 31, 32 during the first operatingphase, but it is not applied to these contacts during the secondoperating phase. If the spinning current scheme would be applied to thesupply-only contacts 31, 32 during the second operating phase, thesupply-only contact 31 would have to act as a sense contact of the firstgroup and the supply-only contact 32 would have to function as a sensecontact of the second group mentioned above. As the supply-only contacts31, 32 are relatively close to the first and second ends of the Halleffect region 11, respectively, the current distribution may be notablyasymmetric in the vicinity of the supply-only contacts 31, 32, which islikely to degrade a performance of the vertical Hall sensor with respectto reducing the zero-point error as much as possible.

During the second operating phase, seven sense elements V9 to V15 areused in order to sense seven differential voltages between pairs ofsense contacts. On the basis of the differential voltages sensed ormeasured by the sense elements V1 to V8 during the first operating phaseand of the sense elements V9 to V15 during the second operating phase,an output signal of the vertical Hall sensor may be determined, forexample, by means of a linear combination of the various differentialvoltages.

As an option, the floating contacts 63-1 and 63-5 may be used assupply-only contacts during the second operating phase, as indicated inthe bottom half of FIG. 1 c by the dashed lines, in order to furtherimprove the symmetry of the current distribution during the secondoperating phase. In this case, the vertical Hall sensor would comprisefour supply-only contacts, 63-1, 31, 32, and 63-5 (having the ordinalnumbers #1, #2, #20, and #21, respectively). The four supply-onlycontacts comprise two outermost supply-only contacts which may be spacedapart from the first and the second end by a distance greater than amaximal spacing of the at least four spinning current contacts.

The operation of the vertical Hall sensor shown in FIG. 1 c may besummarized as follows (the contacts will be referred to by means oftheir ordinal numbers). In the first operating phase, the electriccurrent flows from contact #2 to #4, #6 to #4, #6 to #8, #10 to #8, #10to #12, #14 to #12, #14 to #16, #18 to #16, #18 to #20. The voltages aretapped at the contacts in between the supply contacts whereby thepotential at contacts #5, #9, #13, #17 goes up (under the action of aparticular By field) wherein the potential at the contacts #3, #7, #11,#15, and #19 goes down. The eight sense elements or voltmeters V1 . . .V8 may be used to measure these signals differentially.

In the second operating phase the current flows from contacts #3 to #5,#7 to #5, #7 to #9, #11 to #9, #11 to #13, #15 to #13, #15 to #17, #19to #17. The voltages are again tapped at the contacts in between thesesupply contacts. Whenever the potentials in the first operating phase atcontacts #5, #9, #13, #17 increase due to a By field, the potentials inthe second operating phase at contacts #6, #10, #14, #18 also increasewhile the potentials in operating phase 2 at contacts #4, #8, #12, #16decrease. One may measure these potentials with the seven sense elementsor voltmeters V9 . . . V15.

Note that we can regard the device reaching from contact #3 to contact#5 in the second operating phase as a basic building block, whose mirrorcounterpart is placed to its right, then again mirrored at the rightedge and placed to the right, then again mirrored at the right edge,etc. Therefore, the current consumption of a long strip as the Halleffect region increases, because several current paths are connected inparallel. As a countermeasure, the width (i.e., the extension of thecontacts and the Hall effect region 11 in y-direction) may be keptsmall. Anyhow, several devices are typically connected in parallel inorder to reduce the resistance and the noise of the output signal. Threeoptions may be considered: (i) use several devices in several Halleffect regions and connect them in parallel by wires, (ii) use a widerHall effect region 11 and wider contact strips to reduce the internalresistance, and (iii) use a longer strip with more contacts with anarrow Hall effect region and narrow contacts. From these three optionsnumber (iii) is typically desired in one embodiment, because theinfluence of the asymmetries at the right and left edges are morestrongly reduced than with the other solutions. Usually, the spacing ofthe contact scales with the depth (i.e., the extension into the drawingplane in FIG. 1 c) of the Hall effect region. The depth is in the orderof 5 μm in modern CMOS processes, such as 2 μm, 3 μm, 4 μm, 5 μm, 6 μm,7 μm, 8 μm, or 9 μm. Therefore, the spacing of the contacts is similar(+/−1 μm or +/−2 μm). Thus, a device with 21 contacts may be about 130μm long in one embodiment (or more generally between 50 μm and 250 μm,depending on the contact spacing) which is acceptable for mostapplications.

In FIG. 1 c, separate voltmeters V1 to V15 are depicted that are used tomeasure the output voltages of neighboring cells or basic buildingblocks. Two neighboring voltages can be subtracted and all these termscan be summed up to get the total signal per operating phase. Ingeneral, a linear combination of the readings of the voltmeters V1 to V8and of the voltmeters V9 to V15 may be used. As another option it isalso possible to compute the average of the outputs of the voltmeters V1to V8 and also the average of the outputs of the voltmeters V9 to V15.This may be done by hardware when contacts #3, #7, #11, #15, #19 aretied together and contacts #5, #9, #13, #17 are tied together in thefirst operating phase. The potential may then be measured between thesetwo nodes. Doing so may, however, result in reduced performance(meaning: larger residual zero-point error), because due to mismatchthere will typically be current flowing between the output port and thisleads to larger zero-point errors. One elegant way to compute theaverage of all output voltages in an isolated way is to split up thelarge MOSFETs of the differential input pair of a pre-amplifier (i.e.,the first amplifier connected to the outputs of the Hall devices) and toconnect the voltmeter V1 to the first part of it, the voltmeter V2 tothe second, the voltmeter V3 to the third, etc. This method reduces thenoise, but does not increase the signal.

FIG. 1 d shows a schematic top view of a vertical Hall sensor with sevenidentical contacts numbered 1 to 7 in the Hall effect region 11 arrangedon a regular grid along the x-axis in order to measure By fields. Duringthe first operating phase the contacts 21-1 and 21-2 (#1 and #5,respectively) are configured to function as positive supply contacts.The contacts 22-1 and 22-2 (#2 and #7, respectively) are configured tofunction as negative supply contacts during the first operating phase.The sense contact 23, (#4) is substantially located in the middle of theHall effect region 11 and is connected to a positive input of a firstsense element V1 and a negative input of a second sense element V2. Twoother sense contacts 24-1 and 24-2 are also connected to the first andsecond sense elements V1, V2. The supply contacts 21-1, 21-2, 22-1, and22-2 are connected to one or two voltage supplies of the voltagesupplies 81, 82, 83.

In the second operating phase only two voltage supplies 81, 82 are usedto supply electric energy to the vertical Hall sensor. All sevencontacts of the vertical Hall sensor are spinning current contacts sothat the former supply contacts 21-1, 22-1, 21-2, and 22-2 function assense contacts during the second operating phase. The contacts 23, 24-1and 24-2 function as supply contacts and are thus connected to thevoltage supplies 81, 82 in the manner depicted in FIG. 1 d. A firstdifferential voltage may be tapped between the contacts 22-1 and 21-2 bymeans of the sense element or voltmeter V1. A second differentialvoltage may be tapped as a second sense signal between the sensecontacts 21-1 and 22-2 by means of the sense element or voltmeter V2.Note that the two sense elements V1 and V2 tap their respectivedifferential voltages in a nested manner with respect to the sequence ofthe seven contacts.

The vertical Hall sensor shown in FIG. 1 d has an odd number of contacts(7 or 11 or 15; FIG. 1 d illustrates a configuration having sevencontacts). The symmetry may be increased by using the outmost contacts21-1 and 22-2 as supply (=input) contacts in the first operating phaseand as sense (=output) contacts in the second operating phase. Moreover,they may have different polarity in both phases, as illustrated in FIG.1 d: in the first operating phase one of the outmost contacts is atpositive potential (contact 21-1 having ordinal number 1 in FIG. 1 d)while the other one is at negative potential (contact 22-2 havingordinal number 7 in FIG. 1 d). In the second operating phase one of theoutputs increases with an applied magnetic field By, whereas the otherone decreases (compare the contacts 21-1 (#1) and 22-2 (#7) in thesecond operating phase in FIG. 1 d). Note that in the second operatingphase the electric potential (without applied magnetic field) at contact21-1 is different from the electric potential at contact 22-1, yet the(common mode) potentials at the contact 21-1 and 22-2 are identical andthe (common mode) potentials at 22-1 and 21-2 are also identical due tosymmetry. Therefore, the output signals may be measured between thecontacts 21-1 and 22-2, as well as between the contacts 22-1 and 21-2and subtract them in order to get a signal of the vertical Hall sensorduring a second operating phase. In the first operating phase the twomeasured voltages between the contacts 24-1 and 23, as well as betweenthe contacts 23 and 24-2 are also subtracted to get a signal of thevertical Hall sensor for the first operating phase. Averaging orlow-pass filtering the output signal of the vertical Hall sensor for thefirst operating phase and the second operating phase yields a relativelyaccurate measurement of the magnetic field in the y-direction with lowzero-point error or offset.

The vertical Hall sensor shown in FIG. 1 d uses three voltage supplies81, 82, 83 in the first operating phase and only two voltage supplies81, 82 in the second operating phase. Two sense elements or voltmetersV1 and V2 are used in both the first and the second operating phase.

The principle illustrated in FIG. 1 d can be generalized to more thanseven contacts: whenever the potential distribution is symmetric to thecenter in at least one of the operating phases, the differentialvoltages may be measured in a nested way as illustrated in FIG. 2. FIG.2 shows three voltmeters V1, V2, and Vk of a plurality of k voltmeters,which tap differential voltages along the Hall effect region in a nestedmanner. The innermost voltmeter V1 is connected to the two innermostsense contacts while the outermost voltmeter Vk is connected to the twooutmost sense contacts. In the configuration of FIG. 1 d, bottom half,the electric current flows from left to right between the two supplycontacts 24-1 and 23, whereas the electric current flows from right toleft between the two supply contacts 24-2 and 23. This observation canalso be made for a vertical Hall sensor implementing the voltmeterconfiguration shown in FIG. 2: the direction of electric current flow isopposite in the vicinity of the two sense contacts that are connected toone of the k voltmeters V1 to Vk. In summary, the at least four spinningcurrent contacts may comprise an odd number of spinning current contactsequal to or greater than seven. During at least one operating phase ofthe spinning current scheme an even number equal to or greater than fourof the spinning current contacts may be configured to function as sensecontacts. Differential sense signals may be tapped between pairs of thespinning current contacts functioning as sense contacts during saidoperating phase, wherein the pairs are arranged along the path in anested manner.

FIG. 3 shows the schematic plan view or top view of a vertical Hallsensor with two Hall effect regions 11 and 11′. The entire vertical Hallsensor comprises 18 substantially identical contacts of which contactswith the ordinal numbers 1 to 9 are arranged in the first Hall effectregion 11 and contacts with the ordinal numbers 1′ to 9′ are arranged inthe second Hall effect region 11′. Within each of the Hall effectregions 11, 11′ the contacts are arranged on a regular grid along thex-axis in order to a measure magnetic field By in the y-direction.Hence, the vertical Hall sensor may comprise two separate wells formedin a substrate, each having nine contacts. The inputs of the first Halleffect region are contacts 21 and 22 (#6 and #4, respectively) duringthe first operating phase. The corresponding contacts at the second Halleffect region 11′, i.e. contacts 23′ and 24′ (#6′ and #4′, respectively)are used as outputs of the second Hall effect region 11′. The outputs ofthe first Hall effect region 11 are the contacts 23 and 24 (#7 and #5,respectively), while the corresponding contacts 23′ and 24′ (#6′ and#4′, respectively) of the second Hall effect region 11′ are used asinputs. Both output signals (between contacts #5 and #7, as well asbetween contacts #4′ and #6′) are added to give a total output signal inthe first operating phase. In the second operating phase the outputsignals between the contacts #4 and #6, as well as between #5′ and #7′are added to give the total output signal. The sum of both total outputsignals is proportional to the magnetic field in the y-direction By witha greatly reduced zero point error. Both Hall effect regions 11, 11′could be connected at their leftmost and/or rightmost ends or edges.

The first Hall effect region 11 comprises five floating contacts. Threecontacts 64-1, 61, and 63 are arranged to the left of the region wherethe spinning current contacts 21 to 24 are arranged (central portion).Two other floating contacts 62 and 64-2 are arranged on the right sideof the spinning current contacts 21 to 24. The second Hall effect region11′ has three floating contacts 62-1′, 63′, and 61′ at the left side ofthe spinning current contacts 21′ to 24′ and two floating contacts 64′,62-2′ on the right of the spinning current contacts 21′ to 24′.

FIG. 4 shows a schematic top view or plan view of another vertical Hallsensor with 18 substantially identical contacts. Nine of thesubstantially identical contacts numbered from 1 to 9 are arranged on afirst Hall effect region 11 and the remaining nine of the substantiallyidentical contacts numbered 1′ to 9′ are arranged on the second Halleffect region 11′. The nine contacts arranged on the same Hall effectregion 11 or 11′ are arranged on a regular grid along the x-axis inorder to measure magnetic fields in the y-direction By. The verticalHall sensor shown in FIG. 4 uses cross-coupled outputs as follows: inthe first operating phase a first output voltage is measured between asense contact 23 of the first Hall effect region 11 and a sense contact24′ of the second Hall effect region 11′ by means of a sense element orvoltmeter V11, so that a voltage at the sense element V11 is equal toV11=V5-V4′, where V5 is the electric potential at the sense contact 23(#5 in the sequence of the first Hall effect region 11) and V4′ is theelectric potential at the sense contact 24′ (#4′ in the sequence of thesecond Hall effect region 11′). A second output voltage is measuredbetween the sense contacts 24 (#7 in Hall effect region 11) and thesense contact 23′ (#6′ for Hall effect region 11′) by means of the senseelement or voltmeter V12 so that V12=V7−V6′, wherein V7 designates theelectric potential at contact #7 of the first Hall effect region 11 andV6′ designates the electric potential at the contact #6′ of the secondHall effect region 11′. The total output voltage for the first operatingphase is computed as the difference of both: Sig1=V11−V12. Similarly, inthe second operating phase the first output voltage is measured betweencontact 22 (#4) and contact 22′ (#5′) by means of a sense element orvoltmeter V21 with a differential voltage V21=V4−V5′, wherein V4 is theelectric potential measured at the sense contact 22 of the first Halleffect region 11 and V5′ is the electric potential at the sense contact22′ of the second Hall effect region 11′. A second output voltage ismeasured between the sense contacts 21 and 21′ by means of a senseelement or voltmeter V22 as a differential voltage V22=V6−V7′, whereinV6 is the electric potential at the sense contact 21 (#6 in Hall effectregion 11) and V7′ is the electric potential at the sense contact 21′(#7′ in the second Hall effect region 11′). A total output voltage iscomputed as the difference of both: Sig2=V21−V22. The difference of bothtotal output voltages is Sig1−Sig2=V11−V12−V21+V22 and is proportionalto the magnetic field in the y-direction By with greatly reducedzero-point error.

Three floating contacts 63-1, 61, and 64 are arranged to the left of thespinning current contacts 21 to 24 in or on the surface of the firstHall effect region 11. Two further floating contacts 62 and 63-2 arearranged to the right of the spinning current contacts 21 to 24.Regarding the second Hall effect region, three floating contacts 62-1′,63′, and 61′ are arranged to the left of the spinning current contacts21′ to 24′ and two floating contacts 64′, 62-3′ are arranged to theright thereof.

FIG. 5 shows a schematic top view or plan view of a vertical Hall sensoraccording to an embodiment of the teachings disclosed herein. Thevertical Hall sensor comprises 16 substantially identical contacts,eight of which are arranged in or on the surface of the first Halleffect region 11 and the remaining eight contacts are arranged in or onthe surface of the second Hall effect region 11′. In or on the surfaceof the first and second Hall effect regions 11, 11′ the correspondingcontacts are arranged on a regular grid along the x-axis in order tomeasure magnetic fields in the y-direction By. The configuration of thevertical Hall sensor shown in FIG. 5 uses cross-coupled outputs of thefirst and second Hall effect regions 11, 11′.

For the first Hall effect region 11 the spinning current contacts arethe contacts having ordinal numbers between 2 and 7 and for the secondHall effect region 11′ the spinning current contacts are the contactshaving ordinal numbers between 2′ and 7′. The outmost contacts in or oneach Hall effect region 11, 11′ are supply-only contacts. In particular,the first Hall effect region 11 has a supply-only contact 31 which isconnected to a positive pole of the voltage supply during the firstoperating phase of the spinning current scheme. A second supply-onlycontact 33 formed in or on the first Hall effect region 11 is leftfloating during the first operating phase. With respect to the secondHall effect region 11′ a supply-only contact 32′ is connected to anegative pole of the voltage supply during the first operating phase.The other supply-only contact 34′ is left floating during the firstoperating phase.

During the second operating phase the supply-only contact 31 of thefirst Hall effect region 11 is left floating, while the othersupply-only contact 33 of the first Hall effect region 11 is nowconnected to the negative pole of a voltage supply and thus functions asa supply contact. The left supply-only contact 32′ of the second Halleffect region 11′ is also left floating during the second operatingphase, whereas the right supply-only contact 34′ of the second Halleffect region 11′ is connected to a positive pole of a voltage supply,i.e., the supply-only contact 34′ functions as a supply contact duringthe second operating phase.

Regarding the symmetry of the vertical Hall sensor, the contacts havingordinal numerals 8 and 8′ are floating while the leftmost contacts withordinal numbers 1 and 1′ are at reference and supply potential,respectively, during the first operating phase. During the secondoperating phase the contacts with ordinal numbers 1 and 1′ are floatingwhile the rightmost contacts are at reference and supply potentials,respectively. In one embodiment, the spacing in y-direction between thefirst and the second Hall effect regions, 11, 11′ is small (e.g., <10μm). The spacing depends on the application: if the application hashomogeneous fields, the spacing can also be larger and, for example, aconventional Hall plate for measuring magnetic field componentsperpendicular to the surface of the Hall effect regions 11, 11′ could beinserted in between the first and second Hall effect regions 11, 11′.

Three differential voltages are tapped in a Hall effect region-spanningmanner during the first operating phase. A first differential voltageV11 is tapped between the contacts 23-1 and 24-1′ by means of acorresponding sense element or voltmeter. A second differential signalV12 is tapped between the contacts 24 and 23′. A third differentialvoltage V13 is tapped between the sense contacts 23-2 and 24-2′. Duringthe second operating phase three further differential voltages V21, V22,and V23 are tapped in a Hall effect region-spanning manner. The sixdifferential voltages measured during the first and the second operatingphase may be processed in a similar manner to what has been explained inconnection with FIG. 4. In particular a linear combination of thedifferential voltages V11 to V23 may be determined.

When examining the contact configurations of the first and second Halleffect regions 11, 11′ it can be seen that the functions of the variouselectrodes numbered 1′ to 8′ of the second Hall effect region 11′ aresubstantially complementary to the functions of the correspondingcontacts numbered 1 to 8 of the first Hall effect region 11. Forexample, the contact having the ordinal number 1 in the sequence of thefirst Hall effect region 11 functions as a positive supply contactduring the first operating phase, while its counterpart having theordinal number 1′ in the second Hall effect region 11′ functions as anegative supply contact during the first operating phase. Similarobservations can be made for the remaining contacts 2 to 8 and theircorresponding contacts 2′ to 8′. The contacts of the first Hall effectregion 11 and the contacts of the second Hall effect region 11′ are alsocomplementary to each other during the second operating phase.

In order to summarize the embodiment of the vertical Hall sensor shownin FIG. 5: The vertical Hall sensor may further comprise a further Halleffect region 11′ in, or on a surface of which, is formed a furtherplurality of contacts similar to the plurality of contacts formed in oron the surface of the Hall effect region 11. The further plurality ofcontacts is configured to function in a complementary manner to theplurality of contacts. During each operating phase of the spinningcurrent scheme at least one first sensor signal is tapped between atleast two of the spinning current contacts of the plurality of contactsformed in or on the surface of the Hall effect region and at least onesecond sense signal is tapped between at least two spinning currentcontacts of the further plurality of contacts formed in or on thesurface of the further Hall effect region, and wherein the at least onefirst sense signal and the at least one second sense signal are added orsubtracted from each other by an output signal determiner of thevertical Hall sensor. The further Hall effect region 11′ issubstantially parallel to the Hall effect region 11. The spinningcurrent contacts of the Hall effect region 11 and the further Halleffect region 11′ between which the sense signal is tapped have acorresponding position within the plurality of contacts and the furtherplurality of contacts, respectively. A plurality of the spinning currentcontacts functioning as supply contacts and of the supply-only contactis inversed between the Hall effect region 11 and the further Halleffect region 11′ for a particular operating phase of the spinningcurrent scheme (i.e., contacts at corresponding positions in the Halleffect region 11 and the further Hall effect region 11′ have oppositeelectric polarities), so that directions of electrical current flow areopposite to each other in corresponding portions of the Hall effectregion and the further Hall effect region.

FIG. 6 shows schematic plan views of a vertical Hall sensor during afirst operating phase and a second operating phase. The vertical Hallsensor comprises a single Hall effect region 11 and a plurality of 20substantially identical contacts. The 20 substantially identicalcontacts are arranged along a straight line or path (coinciding with thex-axis) in an evenly spaced manner. The contacts are numbered in arising order of their x-coordinates in a same manner as elsewhere withinthe description of the other figures herein. The 20 substantiallyidentical contacts are spinning current contacts and they are configuredto alternatingly function as supply contacts and sense contactsaccording to a spinning current scheme. Every fourth contact is shorted:thus, contact 21-1 (#1) is shorted to contact 21-2 (#5), 21-3 (#9), 21-4(#13), and 21-5 (#17), resulting in a single node N1 (dotted line inFIG. 6). In a similar manner the contacts 22-1 to 22-5 having ordinalnumerals #3, #7, #11, #15, and #19 are shorted (dashed line) resultingin a single node N3. Shorting the contacts 23-1 to 23-5 (widelydash-dotted line) results in a single node N4. Finally, the contacts24-1 to 24-5 (ordinal numerals #2, #6, #10, #14, and #18) are shorted(narrowly dash-dotted line) which results in a single node N2. Shortingthe various spinning current contacts thus gives four nodes N1, N2, N3,N4. In a first operating phase electrical power is supplied betweennodes N1 and N3 and the signal is tapped between N2 and N4. In a secondoperating phase electrical power is supplied between nodes N2 and N4 andthe signal is tapped between N1 and N3. There is no need for switches orother electronic devices to short the contact 21-1 to 21-5 to the nodeN1; this is done merely via a low ohmic conductor like aluminum wires orstrips on the die. In this manner it may be avoided that switches addresistances that are different in the first and second operating phases,as this could give rise to errors in the spinning current technique.

The idea behind the vertical Hall sensor as shown in FIG. 6 is thefollowing: there are several Hall devices in parallel: the first Halldevice comprises contacts 21-1 (#1), 24-1 (#2), and 22-1 (#3). Usingonly the ordinal numbers to designate the contacts, the second Halldevice comprises the contacts #3, #4, and #5. The third Hall devicecomprises the contacts #5, #6, and #7, etc. Finally, a ninth Hall devicecomprises the contacts #17, #18, and #19. Each Hall device has anindividual stochastic offset (zero-point error). The connection ofcontacts effectively is a parallel circuit of all these devices. Thetotal current splits up into nine substantial equal parts, each oneflowing through one of the nine Hall devices. The outputs are alsoconnected in parallel: this produces an average of all outputs. Inparticular, it produces an average of the total offset error: the meantotal offset error is sqrt(9) times smaller than the offset of a singledevice.

Moreover, the parallel circuit of an odd number of individual Halldevices makes the total device more symmetric: in the first operatingphase the positive supply contact 21-1 (#1) is close to one end of theHall effect region 11, while a sense contact 23-5 (#20) is close to theopposite end of the Hall effect region 11. In the second operating phasewe have similar conditions: the positive supply contact 23-5 (#20) isclose to one end of the Hall effect region 11, while a sense contact21-1 (#1) is close to the other end of the Hall effect region 11. Hence,the unavoidable asymmetries at the end of the Hall effect region(s) aresubstantially identical in both operating phases: consequently, they arelikely to cancel almost completely if the signals of the first and thesecond operating phases are added/subtracted.

Furthermore, there is substantially no asymmetry between the first andthe second operating phases for the inner contact, just the (nearperfect) exchange of supply contacts with sense contacts which gives ahighly accurate spinning current technique.

Note that the current consumption increases by a factor of 9 comparedwith a single device. On the other hand, the noise decreases due to thevery same fact. The current drain can be kept at a minimum if thecontacts are small and the width of the contacts and of the Hall effectregion(s) in y-direction are small.

FIG. 7 shows schematic plan views of a vertical Hall sensor according toan embodiment of the teachings disclosed herein in a configuration for afirst operating phase (top) and a configuration for a second operatingphase (bottom). The vertical Hall sensor shown in FIG. 7 is derived fromthe vertical Hall sensor shown in FIG. 6.

The vertical Hall sensor shown in FIG. 7 comprises 24 substantiallyidentical contacts that are arranged in or on the surface of the Halleffect region 11. Spinning current contacts are arranged in a centralportion of a path extending between a first end (e.g., the left end) anda second end (e.g., the right end) of the Hall effect region 11, alongwhich the plurality of contacts is arranged. The central portionsubstantially begins to the left of the spinning current contact 21-1and ends substantially to the right of the spinning current contact23-5. Two supply-only contacts 32, 33 are arranged to the left of thecentral portion and two other supply-only contacts 31, 34 are arrangedto the right of the central portion. Each spinning current contactwithin the central portion is connected to one of four nodes N1, N2, N3,and N4, depending on its position in the sequence of the contacts.Reference is made to the description of FIG. 6 regarding this aspect.Each supply-only contact is connected to one of the nodes N1 to N4 viaone of four switches SW1, SW2, SW3, and SW4. The supply-only contact 32is connected via switch SW1 to the node N3. The supply-only contact 33is connected via the switch SW2 to the node N4. The supply-only contact31 is connected via the switch SW3 to the node N3. The supply-onlycontact 34 is connected via the switch SW4 to the node N2.

During the first operating phase, the supply-only contact 32 acts as anegative supply contact because the switch SW1 is closed and connectedto the negative pole of the voltage supply 81. The supply-only contact33 is left floating because the switch SW2 is open during the firstoperating phase. The supply-only contact 33 functions as a positivesupply contact because the switch SW3 is closed so that a connection ismade to the positive contact of the voltage supply 81. The supply-onlycontact 34 is left floating because the switch SW4 is open during thefirst operating phase.

When passing from the first operating phase to the second operatingphase, the states of the switches S1 to S4 are toggled, i.e., switchesSW1 and SW3 are open while the switches SW2 and SW4 are closed.Accordingly, the supply-only contacts 32 and 31 are floating during thesecond operating phase. The supply-only contact 33 functions as apositive supply contact because due to the closed switch SW2 thesupply-only contact 33 is connected to the node N4 and thus to thepositive pole of the voltage supply 81. The supply-only contact 34functions as a negative supply contact during the second operating phasebecause the switch SW4 is closed so that the supply-only contact 34 isconnected to the node N2 and the negative pole of the voltage supply 81.

The embodiment of the vertical Hall sensor shown in FIG. 7 has a highersymmetry than the vertical Hall sensor shown in FIG. 6. The highersymmetry comes, however, at the expense of slightly increased currentconsumption: with the four switches SW1 to SW4 one supply contact isadded at the left and the right of the central portion, i.e., thespinning current contact, to prolong the range of potential symmetry atboth ends of the Hall effect region 11.

FIGS. 8 and 9 show vertical Hall sensors having Hall effect regions 11that are not straight. As a consequence, the paths that extend between afirst end and a second end of the Hall effect region and along which theplurality of contacts is arranged, are not straight, either.

FIG. 8 shows a vertical Hall sensor in which the Hall effect region 11has an L-shape. The vertical Hall sensor comprises 16 contacts, eight ofwhich are formed in or on the surface of a portion of the Hall effectregion 11 extending in the x-direction, and the remaining eight contactsare formed in or on the surface of a portion extending in they-direction. Contacts having equal functions during a given operatingphase of the spinning current scheme are mutually connected, thusforming a node. Typically, a spinning current contact may fulfill one ofthe following four functions: positive supply contact, negative supplycontact, “positive” sense contact, and “negative” sense contact. Thespinning current contacts 22-1 to 22-4 function as negative supplycontacts during the first operating phase and are connected to the nodeN1. The spinning current contacts 23-1 to 23-4 function as positivesense contacts during the first operating phase and are connected to thenode N2. The spinning current contacts 21-2 to 21-4 function as positivesupply contacts during the first operating phase and are connected tothe node N3. The spinning current contacts 24-1 to 24-4 function asnegative sense contacts during the first operating phase and areconnected to the node N4.

As with other vertical Hall sensors disclosed herein, the contacts aresubstantially identical. Furthermore, the contacts are arranged in anequidistant manner along a polygon curve, here the L-shape. An exceptionof the equidistant spacing between two adjacent contacts of theplurality of contacts is the distance between the two innermost contacts24-2 and 22-3.

FIG. 9 shows another logical Hall sensor that also comprises 16substantially identical contacts formed in or on the surface of a Halleffect region 11. The Hall effect region 11 is arc-shaped. The pathextending between the first end and the second end of the Hall effectregion 11 is also arc-shaped, i.e. a smooth curve. Other possibleconfigurations of the Hall effect region 11 and the path could comprisepiece-wise straight curves. Although not explicitly depicted in FIG. 9,the various spinning current contact may be mutually connected to eachother in a similar manner as shown in FIG. 8. The spinning currentcontacts have an equidistant spacing along the path.

FIG. 10 shows a schematic top view or plan view of a vertical Hallsensor according to an embodiment of the teachings disclosed herein. Thevertical Hall sensor shown in FIG. 7 may be regarded as a predecessorfor the embodiment shown in FIG. 10. The spinning current contacts 21-i,22-i, 23-i, and 24-i are referred to as first type contacts in thecontext of the description of FIG. 10 and FIG. 11. The supply-onlycontacts 31 to 33 are also referred to as first type contacts. Betweenthese contacts of the first type, which are connected to the nodes N1 toN4, additional contacts 65 may be inserted. These contacts of a secondtype are typically located in a symmetric manner between the contacts ofthe first type. One or several of the second type contacts 65 may besituated between each two contacts of the first type. The second typecontact 65 may have another shape or form than the first type contact:in the embodiment of FIG. 10 the second type contacts 65 are only halfas wide as the first type contacts. An effect of the second typecontacts 65 as they are shown in FIG. 10 is that they pull the currentflow towards a middle line 68 of the Hall effect region 11. Furthermore,they pull the current flow towards the surface of the Hall effect region11, i.e., they prevent that the current flows too much into the depth.This may be important for cases in which a semiconductor manufacturingprocess forms a highly conductive buried layer, such as an n+ dopedburied layer (nBL) which could pull the current towards the depth andcause a short-circuit. The first aspect of pulling the current flowtowards the middle line 68 of the Hall effect region may be importantwhen it is not possible that the contacts of the first type, i.e., thespinning current contacts, extend over the entire width of the Halleffect region: in this case, the magnetic sensitivity is reduced due tocomponents of the currents that flow in the y-direction. In order toreduce/prevent these current components, the second type contacts 65 arearranged close to the middle line 68, which pull the current towards themiddle.

As shown in FIG. 11, the second type contacts or floating contacts 65may also be connected to each other in a similar manner as the firsttype contacts. FIG. 11 shows a schematic plan view of a vertical Halldevice according to an embodiment of the teachings disclosed hereinduring the first operating phase. Second type contacts that are to theright of a negative supply contact have the reference signs 61-1 to61-6. Second type contacts that are to the right of a positive sensecontact have the reference signs 62-1 to 62-6. Second type contacts thatare to the right of the positive supply contacts have the referencesigns 63-1 to 63-6. Second type contacts that are to the right ofnegative sense contacts have the reference signs 64-1 to 64-6. Thesecond type contacts with the reference signs 61-1 to 61-6 are connectedto each other and thus form one floating node. The remaining second typecontacts are also connected to each other in groups, thus forming threeother floating nodes. By connecting a second type contact to othersecond type contacts the individual second type contacts are actuallynot floating anymore in the sense of a single contact. Nevertheless, theconnected second type contacts are floating as a network node becausethey are not externally connected to other circuit elements. The nodesN1 to N4 connecting the spinning current contacts have been omitted fromillustration in FIG. 11 for the sake of clarity.

In both FIGS. 10 and 11 the Hall effect region 11 is elongated and maybe a tub formed in a substrate. On the surface of the Hall effect region11 contacts of the first and second types may be placed so that betweeneach two contacts of the first type there are M contacts of the secondtype (M=1 is possible, as well). All contacts are numbered along theHall effect region 11 in ascending order. The contacts 1, 1+4*(1+M),1+2*4*(1+M), . . . 1+N*4*(1+M) are connected with the node N1. Thecontacts 2+M, 2+M+4*(1+M), 2+M+2*4*(1+M), . . . , 2+M+N*4*(1+M) areconnected with the node N2. The contacts 3+2*M, 3+2*M+4*(1+M),3+2*M+2*4*(1+M), . . . , 3+2*M+N*4*(1+M) are connected with the node N3.Finally, the contacts 4+3*M, 4+3*M+4*(1+M), 4+3*M+2*4*(1+M), . . . ,4+3*M+N*4*(1+M) are connected with the node N4.

Typically, the number of first-type contacts is at least eight. In thealternative, the number could be 12 or 16, which is expected to lead toa better performance of the vertical Hall sensor, in particular withrespect to a reduction of the zero-point error.

As shown in FIGS. 8 and 9, the Hall effect region does not necessarilyhave to be straight, i.e., the contacts do not necessarily have to bearranged along a straight line or path. The Hall effect region 11 simplyhas to be elongated and its longitudinal direction may be a smooth curve(a segment of a circle or an ellipse or it may have a L-shape (or apolygon section). The contacts may then be arranged in a sequence alongthis curve.

The connection of individual contacts to a node may be hard-wired whichmeans that in the operating phases of the spinning current scheme theconnections do not have to be changed (it does not necessarily have tobe a fixed wiring by means of a conductor, but it could also be anelectronic element such as a MOS switch which, however, must not beopened in one operating phase and closed in another operating phase).

Typically, the number of the first type contacts is an even number.

In the following FIGS. 12 a to 14 b several vertical Hall sensors areintroduced which achieve a high degree of symmetry by means of aring-shaped Hall effect region. In particular, the contacts of thevertical Hall sensors shown in FIGS. 12 a to 14 b are highly symmetricto each other, because a ring has no start and no end. Therefore, nodistinction has to be made within the plurality of contacts as to whichcontacts count as “inner” contacts and which count as “outer” contacts.Boundary effects affecting the function of the contacts, for examplewith respect to a distribution of an electric current or an electricpotential within the Hall effect region, are substantially the same forall contacts.

FIG. 12 a shows a schematic layout or plan view of a ring-shapedvertical Hall element 100. The ring-shaped vertical Hall element 100 maybe formed in a substrate 101 that may be, for example, a p-dopedsemiconductor or an isolating material. A ring-shaped tub or well 103 isformed within the substrate 101, for example by n-doping the substrate101 at locations where the ring-shaped tub 103 is to be formed. Thering-shaped tub has a 90° symmetry referred to a center 105 of thering-shaped tub 103. As an alternative, the ring-shaped tub 103 couldhave a higher symmetry (e.g., octagonal or circular shapes). Fourcontacts 102 a, 102 b, 102 c, 102 d are formed in or on a surface of aring-shaped tub 103. By means of the four contacts 102 a to 102 delectric connections can be made to the tub 103 at various locationsthereof. The four contacts 102 a to 102 d essentially extend from aninner perimeter 104 a to an outer perimeter 104 b of the ring-shaped tub103.

The surface of the substrate 101 is parallel to the xy-plane. Thering-shaped vertical Hall element 100 is typically indicative ofmagnetic field components parallel to the xy-plane. Magnetic fieldcomponents parallel to the z-direction should not have significantinfluence on the output signal of the device 100.

The device 100 is shown to have two portions of the ring parallel to thex-axis and two portions of the ring parallel to the y-axis. Otherring-shaped vertical Hall elements may be rotated by an arbitrary anglearound the symmetry center 105. For example, another ring-shapedvertical Hall device 100 may have portions of the ring at +/−45° to thex-axis and y-axis.

The four contacts 102 a to 102 d may be configured as spinning currentcontacts with the contacts 102 a and 102 c being supply contacts and thetwo other contacts 102 b and 102 d being sense contacts during the firstoperating phase of the spinning current scheme, for example.

FIG. 12 b shows a schematic cross-section of the device along the x-axisand through the contacts 102 b and 102 c. It can be seen that thecontacts 102 c and 102 b are formed in a surface 106 a of the tub 103and are shallower than the tub 103. As the device 100 is symmetric, thesame holds for the two other contacts 102 a and 102 d which cannot beseen in FIG. 12 b. In order to give an idea of the dimensions involved,the following information is provided: the tub 103 may be about 5 μmthick in the z-direction, whereas the contacts 102 a to 102 d aretypically less than 1 μm thick (preferably 0.2 μm thick) in oneembodiment. Other possible dimensions are, for example: tub thickness of2 μm, 3 μm, 4 μm, 6 μm, 7 μm, or 8 μm and contact thickness of 0.05 μm,0.1 μm, 0.5 μm, or 0.8 μm. The tub 103 may be lightly n-doped with adose of 10¹⁵ cm⁻³ to 10¹⁷ cm⁻³ whereas the contacts 102 a to 102 d maybe strongly n-doped with a dose of more than 10¹⁷ cm⁻³ (e.g. 10¹⁹ cm⁻³).The tub 103 may be identical to an n-epitaxial layer of current CMOSprocesses, where the contacts 102 a to 102 d may be identical to shallown⁺ S/D source-drain contacts. The contacts may be reinforced byadditional n-CMOS wells. At a bottom 106 b of the tub 103 there may be aburied layer 107 as is the case for robust BiCMOS/CMOS processes, butthis is not necessarily so. In case of an epitaxial layer it is oftenthe case that trenches isolate the epitaxial layer and the tub 103laterally from the substrate 101 (these trenches are not shown in FIGS.12 a to 12 c).

FIG. 12 c shows a schematic cross-section of the device along the x-axisand through the center point or symmetry center 105 of the device. Thetwo portions of the tub 103 extending in the y-direction can be seen inthis cross-section. During operation, an electric current flows throughthese portions in the y-direction, i.e., perpendicular to the drawingplane. The total section of each portion is the width of the portiontimes the depth of the tub 103. The width is equal to the distancebetween the inner perimeter 104 a and the outer perimeter 104 b of thering-shaped tub 103. However, when the optional n-buried layer 107 ispresent, a significant portion of the electric current is likely to flowwithin the n-buried layer 107.

FIG. 13 a shows a schematic layout or plan view of a ring-shapedvertical Hall device 200. FIG. 13 a also shows schematically how it isconnected in a circuit. Two diagonally opposite contacts 202 b and 202 dare connected to an electric supply 220. The electric supply can be acurrent or a voltage source; a current source 220 is shown in FIG. 13 a.At the other two diagonally opposite contacts 202 a and 202 c the outputsignal 222 a is measured. The output signal 222 a can be the outputvoltage measured with a high-impedance volt meter 221. As analternative, an output current could be measured by means of alow-impedance ampere meter.

In cases in which no magnetic field is present, the output voltage wouldideally be 0: half the current flows between the contacts 202 b and 202d over the right branch of the ring that contains the contact 202 a,whereas the other half of the current flows between the contacts 202 band 202 d over the left branch of the ring that contains the contacts202 c. In practice the output voltage is usually different from 0 due tounavoidable asymmetries in the geometry or in the connectivity of thedevice 200.

If there is a magnetic field component Bx< >0 while By=0, this fieldacts on the charge carriers flowing through branches 203 cd and 203 ab.If there is a magnetic field component By< >0 while Bx=0, this fieldacts on the charge carriers flowing through branches 203 ad and 203 bc.

Suppose Bx>0 and By=0: if the current flows into the contact 202 d andout of the contact 202 b, then the electrons in the tubs 203 ab and 203cd mainly flow in positive y-direction. Strictly speaking, the electronsflow in semi-arcs because they enter the tub at the contact 202 b andflow simultaneously into the depth (=negative z-direction=into thedrawing plane) of the tub 203 ab and toward the contact 202 a. Afterapproximately half of the length of the tub portion 203 ab, theelectrons flow up toward the surface where the contact 202 a is (=inpositive z-direction=out of the drawing plane). Due to the Lorentz-Forceof the Bx-fields on the electrons, they are pulled towards the surfaceof the tub (106 a in FIGS. 12 b, 12 c). This is due to the Hall effect:the Hall effect pulls the electrons on smaller, shallower semi-arcs.This happens in both tubs 203 ab and 203 cd. Consequently, the electricpotential at the contact 202 a is lowered, whereas the electricpotential at contact 202 c is raised and therefore the signal 222 aincreases due to the action of a positive Bx-field. Note that the outputsignal 222 a is positive if the input signal at the non-inverting inputdenoted with a “+” is larger than the input signal at the invertinginput denoted with a “−”.

Suppose now that the magnetic field in the y-direction By>0 and Bx=0:the Lorentz-Force on the electrons flowing through the tub portions 203ad and 203 bc again pulls them to the surface of the tub, whichdecreases the resistance of these tubs. The electrons flowing in theother two branches of the tub, i.e., the tub portions 203 ab and 203 cd,are not affected by the By-component because it is parallel to the driftvelocity. Consequently, the electric potential at the contact 202 a israised and the electric potential at the contact 202 c is lowered sothat the signal 222 a decreases.

In summary, the output signal 222 a is proportional to the difference ofthe magnetic field components in the x- and y-directions Bx and By:S_(out(222a))=K*(Bx−By) with K>0. The factor of proportionality K isequal for both components Bx and By as long as the device has at least a90° symmetry (in our case the tub portion 203 ad is equally long as thetub portion 203 ab). Changing the current direction causes the outputsignal S_(out(222a)) to change its sign.

Exchanging or swapping the inputs and outputs of the ring-shapedvertical Hall device results in the situation shown in FIG. 13 b. IfBx>0 and By=0, the resistances of the tub portions 203 ab and 203 cddecrease and the output signal 222 b is positive. If By>0 and Bx=0, theresistances of the tub portions 203 bc and 203 ad increase and theoutput signal 222 b is positive. The output signal during the secondoperating phase which is illustrated in FIG. 13 b thus depends on themagnetic field components in the x- and y-directions Bx and By, thusS_(out(222b))=K*(Bx+By).

The output signals of both operating phases can be subtracted:S_(out(222a))−S_(out(222b))=K*(Bx−By)−K*(Bx+By)=(−2)*K*By.

At the same time, a zero-point error cancels or is significantlyreduced, as is shown next: suppose that the tub portion 203 ab isslightly longer than the other branches of the device. At vanishingmagnetic fields we get S_(out(222a))=(−1)*Off and S_(out(222b))=(−1)*Offwith Off>0. Therefore, the offset Off vanishes if the two signals forthe two operating phases are subtracted: S_(out(222a))−S_(out(222b))=0(for Bx=By=0). Hence, the difference of the signalS_(out(222a))−S_(out(222b)) is proportional to the By field and it is atthe same time substantially free of the zero-point errors of the device.This is the spinning current principle applied to ring-shaped verticalHal devices.

The current direction can be reversed in both FIGS. 13 a and 13 b inorder to have a total of four measuring points for all four currentdirections. If all four values are subtracted an even better spinningcurrent method can be obtained with an output signal that is stillproportional to the magnetic field component in the y-direction By.

Generally, the connections can be changed in many permutations and it isalso possible to rotate the device on the wafer so that the portions ofthe tub 103, 203 may be at an angle to the x-axis different from 0° and90°. The magnetic field components in the x-direction Bx and they-direction By can be measured separately and simultaneously a very lowoffset error or zero-point error can be achieved.

FIGS. 14 a and 14 b show another ring-shaped Hall device 300 a, 300 bwhich is rotated by 45° compared to the ring-shaped Hall device 200 a,200 b shown in FIGS. 13 a and 13 b. The abbreviations nx and ny are usedto designate the unit vectors in the x-direction and the y-direction,respectively. If the magnetic field points into the direction(nx+ny)/sqrt(2), the resistances of the tub portions 303 ad and 303 bcdecrease and thus the output signal 322 a is negative.

If the magnetic field points into the direction (nx-ny)/syrt(2) theresistances of the tub portions 303 ab and 303 cd decrease and thus theoutput signal 322 a is positive.

From this it follows thatS_(out(322a))=−K*(Bx+By)/sqrt(2)+K*(Bx−By)/sqrt(2)=−sqrt(2)*K*By withK>0.

Exchanging or swapping the inputs and the outputs of the device leads tothe configuration which is shown in FIG. 14 b that is used during thesecond operating phase of the spinning current scheme, for example.

If the magnetic field points into the direction (nx+ny)/sqrt(2), theresistances of the tub portions 303 ad and 303 bc increase and thus theoutput signal 322 b is positive.

If the magnetic field points into the direction (nx-ny)/sqrt(2), theresistances of the tub portions 303 ab and 303 cd decrease and thus theoutput signal 322 b is positive.

It follows thatS_(out(322b))=K*(Bx+By)/sqrt(2)+K*(Bx−By)/sqrt(2)=sqrt(2)*K*Bx with K>0.

As with the ring-shaped vertical Hall device 200 a, 200 b shown in FIGS.13 a, 13 b, the zero-point error or offset can be significantly reducedwhich can be demonstrated by similar calculations. Supposing again thatthe tub portion 303 ab is slightly longer than the other branches, atzero magnetic field the two output signals for the two operating phasesare: S_(out(322a))=(−1)*Off and S_(out(322b))=(−1)*Off with Off>0.

Therefore, this zero-point error can be cancelled by subtracting theoutput signals of the two operating phases; S_(out(322a))−S_(out(322b)).This leads to the following equation:S _(out(322a)) −S_(out(322b))=−2*K*By/sqrt(2)−2*K*Bx/sqrt(2)=−sqrt(2)*K*(Bx+By).

The ring-shaped vertical Hall devices 200 and 300 shown in FIGS. 13 a,13 b and 14 a, 14 b, respectively, may be combined to form a measurementsystem. Such a measurement system including both devices 200 and 300 iscapable of computing the magnetic field components Bx and By separately.It is possible to arrange both devices side-by-side. Yet, one may alsoplace one device inside the inner perimeter of the other device in orderto have identical centers of symmetry 105.

The vertical Hall sensors or devices disclosed herein may be modified orfurther specified by means of one or more of the followingconfigurations, structures, and/or measures. One or more p-isolationtubs may be inserted between the n⁺ contacts, i.e., between any two ormore contacts that are formed in or on the surface of the Hall effectregion or tub. The p-isolation tubs may be used to achieve a certaindesired current density distribution within the Hall effect region ortub, for example by preventing that a significant portion of theelectric current flows near the surface of the Hall effect region ortub.

Especially with respect to the ring-shaped vertical Hall devices 100,200, 300 shown in FIGS. 12 a to 14 b, the tubs may be circular oroctagonal. As another option, a multitude of ring-shaped vertical Halldevices may be used. The multitude of ring-shaped vertical Hall devicesmay be arranged in an array, a grid, or a cross-shaped arrangement, forexample.

The vertical Hall sensors or devices may comprise an n⁺ buried layer(nBL) or not. If an n⁺ buried layer is present, this n⁺ buried layer maybe interrupted between the different sections of a Hall effect region orportions of a tub, if this is technologically feasible with thesemiconductor manufacturing process used for manufacturing a particularvertical Hall effect sensor or device.

With respect to the ring-shaped vertical Hall devices, the number ofcontacts may be reduced to three contacts only. In this case, thering-shaped vertical Hall device would comprise two supply contacts andonly one sense contact. Instead of measuring a differential sense signalbetween two sense contacts, a sense signal would be measured at thesingle sense contacts referred to a reference potential, such as aground potential.

FIG. 15 shows a schematic flow diagram of a magnetic sensing methodaccording to an embodiment of the teachings disclosed herein. During afirst action 152 a power supply is connected between a spinning currentcontact and a supply-only contact of a Hall effect region. The spinningcurrent contact is configured to function alternatingly as a supplycontact and as a sense contact according to the spinning current scheme.The spinning current contact and the sense contact belong to a pluralityof contacts formed in or on the surface of the Hall effect region of avertical Hall sensor comprising at least four spinning current contactsand at least two supply-only contacts. The contacts are arranged in asequence along a path extending between a first end and a second end ofthe Hall effect region, wherein the at least four spinning currentcontacts are arranged along a central portion of the path, and whereinthe at least two supply-only contacts are arranged on both sides of thecentral portion in a distributed manner. The supply-only contacts areconfigured to supply electrical energy to the Hall effect regionaccording to an extension of the spinning current scheme for supplyingelectrical energy to the Hall effect region.

A sense signal is sensed during an action 154 between at least twospinning current contacts currently functioning as sense contacts.

Then, at an action 156, the functions of the spinning current contactsare swapped so that the electrical energy is now supplied to the Halleffect region via one of the spinning current contacts that haspreviously functioned as a sense contact and at least one othersupply-only contact different from the supply-only contact usedpreviously, i.e., during the actions 152 and 154.

During an action 158 another sense signal is sensed between two spinningcurrent contacts other than the ones used previously as sense contacts.

At an action 159 an output signal is determined on the basis of thesense signals obtained during the actions 154 and 158. The magneticsensing method may then be repeated for another cycle of the spinningcurrent scheme.

Although some aspects have been described in the context of anapparatus, it is clear that these aspects also represent a descriptionof the corresponding method, where a block or device corresponds to amethod step or a feature of a method step. Analogously, aspectsdescribed in the context of a method step also represent a descriptionof a corresponding block or item or feature of a correspondingapparatus. Some or all of the method steps may be executed by (or using)a hardware apparatus, like for example, a microprocessor, a programmablecomputer or an electronic circuit. In some embodiments, some one or moreof the most important method steps may be executed by such an apparatus.

The above described embodiments are merely illustrative for theprinciples of the present invention. It is understood that modificationsand variations of the arrangements and the details described herein willbe apparent to others skilled in the art. It is the intent, therefore,to be limited only by the scope of the impending patent claims and notby the specific details presented by way of description and explanationof the embodiments herein.

What is claimed is:
 1. A vertical Hall sensor, comprising: a Hall effectregion; a plurality of contacts formed in or on a surface of the Halleffect region, the contacts being arranged in a sequence along a pathextending between a first end and a second end of the Hall effectregion; wherein the plurality of contacts comprise at least fourspinning current contacts and at least two supply-only contacts; whereinthe spinning current contacts are configured to alternatingly functionas supply contacts and sense contacts according to a spinning currentoperation; wherein the at least four spinning current contacts arearranged along a central portion of the path; and wherein the at leasttwo supply-only contacts are arranged on opposing sides of the centralportion in a distributed manner and are configured to supply electricalenergy to the Hall effect region; wherein two of the at least fourspinning current contacts and one of the at least two supply-onlycontacts are configured to supply electrical energy to the Hall effectregion and two other spinning current contacts are configured tofunction as sense contacts during a first operating phase of thespinning current operation, and wherein the two spinning currentcontacts functioning as sense contacts during the first operating phaseand the other of the at least two supply-only contacts are configured tosupply electrical energy to the Hall effect region during a secondoperation phase of the spinning current operation, and wherein the twospinning current contacts having functioned as supply contacts duringthe first operating phase are configured to function as sense contactsduring a second operating phase of the spinning current operation. 2.The vertical Hall sensor according to claim 1, wherein the Hall effectregion is elongated and has one of a straight shape, a curved shape, anangled shape, an L-shape, an arched shape, and a piece-wise straightshape.
 3. The vertical Hall sensor according to claim 1, wherein theplurality of contacts comprises at least four of the supply-onlycontacts so that during at least two operating phases of the spinningcurrent operation at least one supply-only contact at each side of thecentral portion is configured to supply electrical energy to the Halleffect region.
 4. The vertical Hall sensor according to claim 1, whereinthe at least two supply-only contacts comprise two outermost supply-onlycontacts that are spaced apart from the first end and the second end bya distance greater than a maximal spacing of the at least four spinningcurrent contacts.
 5. The vertical Hall device according to claim 1,wherein a length of the Hall effect region is greater than a length ofthe central portion by a factor comprised in a range between 1.2 and 20.6. The vertical Hall sensor according to claim 1, further comprising atleast two floating contacts, wherein a first of the at least twofloating contacts is formed in or on the surface of the Hall effectregion between the first end and one of the at least two supply-onlycontacts that is closer to the first end than the other(s) of the atleast two supply-only contacts; and wherein a second floating contact ofthe at least two floating contacts is formed in or on the surface of theHall effect region between the second end and one of the at least twosupply-only contacts that is closer to the second end than the other(s)of the at least two supply-only contact.
 7. The vertical Hall sensoraccording to claim 1, wherein the at least four spinning currentcontacts comprise an odd number of spinning current contacts equal to orgreater than seven, wherein during at least one operating phase of thespinning current operation an even number equal to or greater than fourof the spinning current contacts are configured to function as sensecontacts, and wherein differential sense signals are tapped betweenpairs of the spinning current contacts functioning as sense contactsduring said operating phase, wherein the pairs are arranged along thepath in a nested manner.
 8. The vertical Hall sensor according to claim1, further comprising a further Hall effect region in, or on a surfaceof which, is formed a further plurality of contacts similar to theplurality of contacts formed in or on the surface of the Hall effectregion, wherein the further plurality of contacts is configured tofunction in a complementary manner to the plurality of contacts, andwherein during each operating phase of the spinning current operation atleast one first sensor signal is tapped between at least two of thespinning current contacts of the plurality of contacts formed in or onthe surface of the Hall effect region and at least one second sensesignal is tapped between at least two spinning current contacts of thefurther plurality of contacts formed in or on the surface of the furtherHall effect region, and wherein the at least one first sense signal andthe at least one second sense signal are added or subtracted from eachother by an output signal determiner of the vertical Hall sensor.
 9. Thevertical Hall sensor according to claim 1 further comprising a furtherHall effect region and a further plurality of contacts formed in or onthe surface of a further Hall effect region, the plurality of contactsand the further plurality of contacts being substantially similar;wherein at least one sense signal is tapped between a spinning currentcontact formed in or on the surface of the Hall effect region and aspinning current contact formed in or on the surface of the further Halleffect region, both functioning as a sense contact during a sameoperating phase of the spinning current operation.
 10. The vertical Hallsensor according to claim 9, wherein the further Hall effect region issubstantially parallel to the Hall effect region, and wherein thespinning current contacts of the Hall effect region and the further Halleffect region between which the sense signal is tapped have acorresponding position within the plurality of contacts and the furtherplurality of contacts, respectively, and wherein a plurality of thespinning current contacts functioning as supply contacts and of thesupply-only contact is inversed between the Hall effect region and thefurther Hall effect region for a particular operating phase of thespinning current operation, so that directions of electrical currentflow are opposite to each other in corresponding portions of the Halleffect region and the further Hall effect region.
 11. The vertical Hallsensor according to claim 1, wherein the at least two supply-onlycontacts comprise at least four switched supply-only contacts, each oneof the at least four switched supply-only contacts being connected,through a switching element, to at least one of the at least fourspinning current contacts.
 12. The vertical Hall sensor according toclaim 1, further comprising a plurality of floating contacts, wherein Mfloating contacts are arranged between every two spinning currentcontacts, M being a positive integer.
 13. The vertical Hall sensoraccording to claim 1, wherein the two spinning current contactfunctioning as sense contacts during the first operating phase areconnected to a pair of nodes configured to be connected to a voltagesensing element during the first operating phase and are connected toanother pair of nodes configured to be connected to a voltage or currentsupply during the second operating phase together with one of thesupply-only contacts.
 14. A vertical Hall sensor, comprising: a Halleffect region having a first end and a second end and being symmetricwith respect to a symmetry axis such that the first and second ends aremirror-inverted to each other with respect to the symmetry axis; aplurality of contacts formed in or on a surface of the Hall effectregion in a symmetrical manner with respect to the symmetry axis, thecontacts being arranged in a sequence along a path extending between thefirst end and the second end of the Hall effect region; wherein theplurality of contacts comprises at least four spinning current contactsand at least two supply-only contacts; wherein the spinning currentcontacts are configured to alternatingly function as supply contacts andsense contacts according to a spinning current operation; wherein the atleast four spinning current contacts are closer to the symmetry axisthan the supply-only contacts; wherein the at least two supply-onlycontacts are configured to supply electrical energy to the Hall effectregion such that boundary effects affecting an electric current flowwithin the Hall effect region are reduced, the boundary effects beingcaused by at least one of the first and second ends.
 15. A magneticsensing method, comprising: connecting a power supply between a spinningcurrent contact and a supply-only contact, wherein the spinning currentcontact is configured to alternatingly function as a supply contact anda sense contact according to a spinning current operation, wherein thespinning current contact and the supply-only contact belong to aplurality of contacts formed in or on the surface of a Hall effectregion of a vertical Hall sensor comprising at least four spinningcurrent contacts and at least two supply-only contacts, the contactsbeing arranged in a sequence along a path extending between a first endand a second end of the Hall effect region, wherein the at least fourspinning current contacts are arranged along a central portion of thepath, and wherein the at least two supply-only contacts are arranged onboth sides of the central portion in a distributed manner and areconfigured to supply electrical energy to the Hall effect region forsupplying electrical energy to the Hall effect region; sensing a sensesignal between at least two spinning current contacts currentlyfunctioning as sense contacts; swapping the functions of the spinningcurrent contacts so that the electrical energy is now supplied to theHall effect region via one of the spinning current contacts havingpreviously functioned as sense contacts and at least one othersupply-only contact different from the supply-only contact usedpreviously; sensing a sense signal between two spinning current contactsother than the ones used previously; and determining an output signalbased on the sense signals.
 16. The magnetic sensing method according toclaim 15, wherein determining the output signal comprises multiplying atleast one of the sense signals with ±1 and at least one of adding,averaging, and low-pass filtering two or more sense signals.
 17. Themagnetic sensing method according to claim 15, further comprising:switching at least one switching element connected to at least one ofthe supply-only contacts so that the at least one supply-only contact isconfigured to supply electrical energy to the Hall effect region duringat least one operating phase of the spinning current operation and tofunction as a floating contact during at least one other operating phaseof the spinning current operation.
 18. A vertical Hall sensor,comprising: a Hall effect region; and a plurality of contacts formed inor on a surface of the Hall effect region, the contacts being arrangedin a sequence along a path extending between a first end and a secondend of the Hall effect region; wherein the plurality of contactscomprise at least four spinning current contacts and at least twosupply-only contacts; wherein the spinning current contacts areconfigured to alternatingly function as supply contacts and sensecontacts according to a spinning current operation; wherein the at leastfour spinning current contacts are arranged along a central portion ofthe path; wherein the at least two supply-only contacts are arranged onopposing sides of the central portion in a distributed manner and areconfigured to supply electrical energy to the Hall effect region;wherein a first pair of the at least four spinning current contacts areconnected to a first pair of nodes configured to be connected to avoltage or current supply, and a second different pair of the at leastfour spinning current contacts are connected to a second different pairof nodes configured to be connected to a voltage sensing element duringa first operating phase of the spinning current operation; and whereinthe first pair of the spinning current contacts are connected to thesecond pair of nodes, and the second pair of the current contacts areconnected to the first pair of nodes during a second operation phase ofthe spinning current operation.
 19. The vertical Hall sensor accordingto claim 18, wherein the at least two supply-only contacts are floatedduring the first and second operation phases of the spinning currentoperation.
 20. The vertical Hall sensor according to claim 18, whereinthe Hall effect region is elongated and has one of a straight shape, acurved shape, an angled shape, an L-shape, an arched shape, and apiece-wise straight shape.
 21. The vertical Hall sensor according toclaim 18, wherein the plurality of contacts comprises at least four ofthe supply-only contacts so that during at least two operating phases ofthe spinning current operation at least one supply-only contact at eachside of the central portion is configured to supply electrical energy tothe Hall effect region.
 22. The vertical Hall sensor according to claim18, wherein the at least two supply-only contacts comprise two outermostsupply-only contacts that are spaced apart from the first end and thesecond end by a distance greater than a maximal spacing of the at leastfour spinning current contacts.
 23. The vertical Hall device accordingto claim 18, wherein a length of the Hall effect region is greater thana length of the central portion by a factor comprised in a range between1.2 and
 20. 24. The vertical Hall sensor according to claim 18, whereinone of the at least two supply-only contacts is configured to beconnected to the voltage or current supply together with the first pairof the at least four spinning current contacts during the firstoperating phase, and wherein the other of the at least two supply-onlycontacts is configured to be connected to the voltage or current supplytogether with the second different pair of the at least four spinningcurrent contacts during the second operating phase of the spinningcurrent operation.